How does the blue whale produce the "loudest sound of all animals" when mother-in-laws are alive?

OK, first of all, that's mothers-in-law, not mother-in-laws. I cannot abide such sloppy English usage. Secondly, mothers-in-law produce the shrillest sound of all creatures, not the loudest. Blue whales are very loud, but mellow.

Blue whales have a complex family structure, including marriage and therefore mothers-in-law. Given their long life spans and lack of birth control, most female blue whales are mothers-in-law. It's that combination that can be heard for thousands of miles underwater.